One thing, however, is lacking, which involves security and protection against brute force attacks. In my humble opinion, security should be part of every tutorial.

I am using Ubuntu 12.10 and can't figure out the location of the logs that would record the falied SMTP, POP3, IMAP logins.

Would Falko or anyone tell us in which log these records might be, how to enable the logging? How the failed authentication attempts look, so we might set up fail2ban filter to block brute force attacks.